Dual VGA

For NVIDIA users, the dual VGA jack position likely to be reversed, but, usually NVIDIA puts Primary VGA port on the bottom side & Secondary PCI VGA with DVI output is placed on the upper PCI

Or the user can use an application with 2 monitors to display. Such as editing sound tracks that require a large screen so that the sound track can be seen. The example is with Cooledit software to display the one program with two screens simultaneously. To display an application with 2 screens, drag / strecth windows on the application to the left and right side of the screen, like dragging windows screen on monitors.

Or you want to watch a DVD of a movie with 2 monitors. Is the same as showing an application with 2 monitors. In the test program on the DVD, to display the second screen with Power DVD, then the Aspect Ratio must be turned off so the image can be displayed by the program to the left and right. 

2 Monitor 1 application - Power DVD, Aspect Ratio off

The drawbacks of use more than 2 monitors with one computer 

            Use of computers to monitor more than 2 doesn't look as good compared with only 1 or 2 monitors. Display images only good when used as a text display (2D). For applications such as browsers, spreadsheets will not be problematic for a computer with 3 and 4 display monitors. But the 3D image display will remain in place for 2 monitors only. While the DVD images, visual effects such as OpenGL requires a process on the GPU will only be shown at 1 to 2 monitors. Image processing OpenGL and Direct 3D has a limit to 1 and 2 monitors. 

            The preparation sequence of the monitor to 3 and 4 will be different than the use of two monitors. Because the sequence between the two monitors can be set from the driver. And settings can be transferred to move from where you want from the driver.             While more than 2 monitor settings can only be moved as the location of the monitor in the driver. Suppose you are using 4 pieces of the monitor, the setting where the monitor is set of images within each VGA driver setup. But drivers can not adjust the monitor in what priority. Setting 4 monitors will have a 1-3-2-4 sequence. Sequences 1 and 3 is the first display on the VGA and the monitor 2 and 4 connected to a second VGA .